Effective, reliable, safe and economical packaging of bulk products for handling, transport and storage has been a concern for many years. Bulk products requiring such packaging vary widely from semi-solids such as meat and other such food items; to granular materials such as beans, peas, grains, rice, salt, flour, sugar, dry chemicals, dry cementious products, animal feeds, fertilizers, etc.; to liquid materials such as syrups, milk, juices, glues, inks, resins, paints, chemicals, and the like. Since such materials have a tendency to move or flow, containment of them for shipment, handling and storage raises many challenges. It is desirable to package such materials in containers that can be readily transported by truck, rail or ship and that can be easily handled during transport and at a final destination such as at a processing facility by readily available equipment such as fork lifts, cranes and the like. The flowable nature of such products presents unique packaging issues for the container. Movement or shifting of the materials during transport can cause deformation of the container that can result in load shifting and instability and bursting containers, often with enough force to damage or destroy the container. The result is loss or damage to the container contents and undue cleanup and environmental concerns. The containers must even be more stable if stacked on top of each other.
The packaging industry has, to date, generally used two primary containment approaches: (1) corrugated bulk box containers (both plastic and paper); and (2) large bulk bags of woven fabric generally referred to as flexible intermediate bulk containers (FIBCs). Both approaches use various configurations of liners, typically made of polyethylene or polypropylene, that fit within the corrugated bulk box or within the FIBC for preventing contamination of the product being shipped and, in the case of a liquid product, to contain the liquid. Both packaging approaches use containers typically configured to be supported by and carried on pallets.
Utilizing the corrugated bulk box approach, the container strength needed to handle the wide variety of weight and product consistency requirements is addressed by using different strength grades of corrugated board materials and/or by increasing the wall thickness of the boxes by gluing corrugated sheets together or by inserting a corrugated sleeve into the box. Another approach for strengthening the box container is to wrap a number of plastic or steel straps around the outside periphery of the box. Both techniques suffer shortcomings. The price of the bulk box significantly increases with increased wall thickness and/or higher quality corrugated materials. If the box board wall strength and/or thickness is reduced in order to cut costs, and a number of external support straps or bands are used, product pressure against the thinner box walls generally causes the box to bulge outwardly between the straps, resulting in a container having marginal safety factor and leading to numerous costly box failures in shipment.
The FIBCs utilize various fabrics (such as woven polypropylene and PVC coated fabrics) and various fabric weights and sewing methods, depending on the necessary strength of the bag and its desired factor of safety. Such bags vary in size to generally hold from 5 to 120 cubic feet of material and up to about 5,000 pounds of product. They generally can be designed with various shaped tops suitable for filling, can have a solid bottom or a sewn-in discharge spout configuration, and have lifting handles. For dry or fluidized products that require a more rigid bag for stability, solid support inserts may be placed inside the bag, and between the outer bag surface and a liner (if one is used) to provide the bag's sidewalls with more rigidity. Because of the cost of the manufacturing sewing operations and the cost of the rigidity enhancing inserts used in the FIBCs, they typically result in a more expensive container than their corrugated box with strapping counterparts. If used without significant rigidity supports to store liquid materials, the FIBC bag will act like a large water balloon; thereby making the FIBCs more practical for use in shipping and storing dry bulk products instead of liquid or semi-liquid materials. Further, the inserts that are typically placed within the FIBCs to provide sidewall rigidity are typically joined/hinged at their corners to fold down flat when not in use, and do not have bottoms. Without rigid bottoms, the inserts are susceptible to significant deformation from their intended footprint configuration during loading of the FIBC, resulting in a misshaped containment system that is unstable before and during shipment. To address this problem, collapsible metal grid cages have been configured to externally support the FIBC, further adding to the cost and use inflexibility of such systems for containing liquids or semi-liquid materials.
The present invention addresses the problems and shortcomings of both the prior corrugated box and the FIBC containment systems. The present invention combines the strength of woven polypropylene materials used in the FIBC technology with unique configurations of forming members and inserts using corrugated box technology, to create a very strong container that is easy to set up, generally maintains its shape for stacking, which is significantly more cost effective, and which is safer and more reliable than heretofore known packaging methods.